I personally would not be drinking the water from the sprinkler pipes. That stuff would probably kill you faster than anything. It sits in the pipes for years. I've seen the muck that comes out of a sprinkler pipe when it's taken apart, no way I'm drinking that water.

You could always start a fire outside the building, maybe a loading dock area or something or a very small, contained fire in a warehouse area. The sprinklers being activated by heat, rather than smoke, I think that would be possible to accomplish.

With a high ceiling, like a warehouse, stratification should come into play. As the hot gases rise through cooler air, they expand, lose heat, and cool. Then cooler air becomes entrained in the gas plume. The plume cools as it rises to where it's at the same temperature and buoyancy as the surrounding air, it no longer rises. It just spreads out horizontally, even though it's not at ceiling level.

I know you probably already knew this - this was just info for those who don't.

And 90%-95% of the time, my office is my company van.